Various styles of power-driven meat-cutting tools have been devised wherein a ring blade is rotatably mounted on a holder which in turn is mounted on a manually operated, power-driven handle or handpiece. These tools have been used for some time to facilitate the removal of meat from a carcass, primarily in a trimming operation or for removing the meat remains from the bones. These meat-cutting tools are either electrically or pneumatically driven. Some examples of these prior meat-cutting tools are shown in U.S. Pat. Nos. 3,269,010; 3,852,882; 4,179,063; 4,178,683; 4,198,750 and 4,324,043.
These power driven tools or trimming knives as they are generally referred to in the industry, consist of a tubular handle terminating in a generally arcuate shaped front end and formed with a hollow bore extending throughout the longitudinal length of the handle. An annular blade holder is attached to the arcuate front end of the handpiece with the ring blade being removably mounted thereon by various mounting arrangements. The blade is formed with gear teeth extending around the top thereof, which are in driving engagement with a pinion gear rotatably mounted within the bore of the handle adjacent the front end of the handpiece.
In electrically driven knives a flexible cable, one end of which is connected to a motor located adjacent to the work area, enters the rear of the handle and extends through the bore and terminates in a squared end. The squared end is engaged in a complementary shaped opening formed in the rear of the pinion gear for rotatably driving the gear. In pneumatically driven knives a squared shaft end of the air motor is engaged in the rear opening of the pinion gear for driving the gear.
These trimming knives have various size diameter blade holders and cutting blades mounted thereon depending upon the particular meat trimming operation for which the knives are to be used. One particular type such as shown in U.S. Pat. No. Re. 25,947 has a blade with a diameter of approximately five inches. This blade is rotatably supported on a blade holder which is mounted on the end of the handpiece by a pair of adjusting bolts which are threadably engaged in holes formed in a curved end surface of the handpiece. A curved metal retaining member extends partially outwardly along the circumference of the blade and provides support for the blade throughout a predetermined arcuate distance. This mounting arrangement provides three separate attachments or contact points for rotatably mounting the blade on the front end of the handpiece.
Such a blade mounting arrangement has several disadvantages in that when the blade must be removed for sharpening or replacement it is difficult for the operator to perform the same at the meat cutting station since the three blade attachment or mounting bolts must be loosened for removing the blade. These three bolts then must be adjusted to properly mount a new or sharpened blade on the handpiece. Quite often these three bolts are not adjusted properly by the operator and a binding action or excessive vibration will occur between the blade and holder effecting the efficiency of the trimming knife.
Another problem with such prior blade mounting arrangement is that the outermost end of the blade is unsupported by the blade holder and occasionally the operator will "pick up" the knife from the meat during a cutting procedure which will cause the cutting blade to move away from the blade holder permitting meat to enter therebetween causing jamming of the blade with respect to the holder.
U.S. Pat. No. 4,439,924 discloses a trimming knife which attempts to eliminate this blade replacement problem by providing a pivotally mounted arcuate shaped lever or shoe which traps the blade in the blade holder. This patent also attempts to eliminate the wear problem of the blade and housing to provide a satisfactory fit between the rotating blade and housing by means of a thumb screw which presses against the blade retaining shoe. Although the trimming knife of this patent may eliminate some of the problems, it results in a knife of a relatively complicated construction which increases the number of components and correspondingly the number of parts which must be manufactured and assembled and thus increases the cost of the final unit.
Many of these problems have been eliminated by my U.S. Pat. No. 4,494,311. Although this prior trimming knife eliminates many of the problems, it does not provide adjustment to compensate for wearing of the blade and housing which occurs after a period of use. This wear can result in undesirable vibration between the housing and blade. Also this knife requires more parts and manufacturing operations than desired to achieve the rapid blade change feature.
Thus, the need has existed for an improved meat trimming knife of the type using a ring-like cutting blade, in which the knife is provided with means for rotatably mounting the blade on the blade holder and handpiece and which enables an operator to quickly and easily remove and install a blade from and on the holder without requiring special skills for accomplishing the same.